Ana took a sibling class last Sunday at the hospital where I will deliver. While we waited for the teacher to begin the class, the kids looked at a poster of a crying baby boy, a sleeping baby girl, and an awake baby girl.A little boy of about 3 wandered over to the poster with his dad. "Dad, what's that on his belly?"The dad then launched into a way-too-technical-for-a-3-year-old description of umbilical cords. "Oh, and there's his ding-a-ling," the boy replied."Yep. That's his ding-a-ling," Dad responded. Then he made another rookie mistake. "And look at that baby. You're having a baby sister, so your baby won't have a ding-a-ling; she'll look like that."Of course, the next question was, "And what's THAT called?"You could have heard a cricket chirp...